Dual XLR is a dual-mono approach, while a single 4-pin (4-pole) XLR uses the same large-size plug, but adds a pin:
The most common TRRS configuration is often referred to as "the Astell & Kern", because that brand used the 2.5mm TRRS as its balanced headphone plug.
A little-known configuration is referred to as "the Ray Samuels", because he uses it for his balanced output plug. It is square in shape and is also 4-pole:
A few of my custom cables (that came with a used pair of headphones) came from moon-audio.com, which is well-known for its custom cables and customized headphones. What I really liked about the cables was the use of a high-quality plug known as a mini-XLR. I use the US-based markertek as a supplier of the high-end REAN (a sub-brand of Neutrik) connectors -- and at a serious discount compared to Amazon or eBay.
Here's why I like the 4-pin mini-XLR connectors:
- They're much smaller and lighter than XLR plugs.
- They're roughly the size of a 1/4" (6.35mm) stereo plug, but much lighter.
- Unlike TRRS, in which plugging and unplugging causes a series of different electrical connections to occur on the way in and out, the various pins of the mini-XLR go straight in to their one and only electrical connection (just like a full-size XLR plug). If you've ever plugged and unplugged guitar chords into an amplifier when it's on, you know what I'm talking about.
- The mini-XLR plugs connect with a locking mechanism, which I like.
(Picture credit: Me)
(Picture credit: Me)
(Picture credit: Me)
Sorry about my poor artistic skills, but if you're looking to build an adapter cable, this should help.
